Firebed agitating mechanism



ATTORNEYS W. B. CHAPMAN FIREBED AGITATING uEcHANIsu Filed May 1o. 192s :a sheets-sheet 1.

............ /f v x Z 3 Nov. 22, 1932.

Nov. 22, 1932.

W. B. CHAPMAN FIREBED AGITATING MEGHANI SM Filed May 10l 1928 2 She ets-Sheet 2 @www M y. :yr a* Patented Nov. 22, 1932 Y UNITED STATI-:s

PATENT OFFICE WILLIAI D. CHAIN, l' JACKSON HEIGHTS, NEW You IIBEBED AGITAIING ppucltion med I ly 10, 1988. $62131 le. 785m The invention relates to irebed a itation as employed in connection with eit er the complete combustion of the fuel or partial combustion such as is lcmplo ed in making rodur gas. One object o the invention 1s to provide adequate irebed agitatlon by mechanism whichis supported and driven ,from beneath the irebed, thus leaving the space above the irebed entirely unobstructed. This feature of the invention is im ortant in boiler firebeds, for example, w ere the location of the boiler directly above the irebed makes it diflicult, if not impossible, to agitate the lirebed from parts supported or driven from above.

The invention may also include as another feature the combination of an agitating mechanism of the above nature with a fuel underfeed which is also driven from below; thus the rebed may be mechanically conditioned and mechanically fed from underneath, the necessary operations for the continuous combustion of the fuel being carried out mechanically and without taking up J space which may be necessarily employed for other parts of the apparatus in connection with which the. lirebed is employed.

The invention also includes the provision ofy a novel agitating device Working in the ash bed and mechanically driven from beneath, which agitates the firebed from underneath and through the medium of the ash, and assists in ash removal at the proper rate conforming to the rate of the ash pro- J duction.

The invention also includes certain new features relating to the air cooling of the walls which enclose the firebed and the preheating of the air used for combustion.

Further objects and advantages of the invention will be in part obvious and in part specifically point-ed out inthe description hereinafter contained which, taken in conjunction with the accompanying drawings, discloses certain preferred embodiments of the invention, such embodiments, however, are to be considered merely as illustrative of its principles. In the drawings- Fig. 1 is a vertical section through the lower portion of a gas producer having an agitating mechanism constructed in accordance with the invention.

Fiv lais a section taken on line 1a'1a' of 1g. 1, looking in the direction ofthe arrows. l 55 Fig. 2 is a viewsimilar to Fig. 1 but showing a somewhat modified form of the invention.

The invention is illustrated as applied to a frebed 1 enclosed within a circular sideo wall 2 and resting for the most part upon a stationary supporting member 3 which in the present instance extends outwardly from a tuyre hood 4.

In the form of the invention shown in Fig. 5 1 the fuel is fed into the iirebed from underneath, through an upstanding hollow column 5 within the tuyre hood 4, and enclosing a spiral feed screw 6 which is connected at its bottom end with a collar 7 rotatably carried 7 by a stationary bearingmember 8, a suitable driving mechanism such as the gear 9 being connected to the collar kto rotate the screw. Fuel is forcibly fed to the` feed screw 6 in some suitable manner, for example, by means of a further horizontal feed screw 10 which receives fuel from the hopper 11.

In accordance with one feature of the invention the top of the firebed is mechanically conditioned by means of an agitating member 12 as shown in the form of a horizontal arm having fingers 13 extending therefrom and continuously rotated by a driving mechanism located beneath the irebed. As shown the hollow stem 14 of the agitator extends down axially through the feed screw 6, thus having a bearing in the latter, to a driving mechanism which acts automatically to keep the agitator operating in or near the surface of the firebed. In the form of the invention shown in Fig. 1, the stem of the agitator is provided with spiral fins 15 which are en closed by the hub of a worm gear 16', having inwardly projecting inclined lugs 17 which respectively engage the fins 15 and rotate the agitator when the worm gear 16 is turned; however the resistance to rotation whichthe Y stationary irebed imposes upon the agitator becomes greater as the agitator is buried deeper in the irebed and the spiral fins 15 10 slide upwardly on lugs 17 when this resistance becomes abnormally high, thus maintaining the agitator at a point in or near the surface of' the firebed, while if the resistance to turning of the agitator is low, the fins 15 may slide downwardly along lug 17 until a balance is reached between the torsional force exerted by gear 16l and the torsional resistance imposed by the firebed. Thus with varying resistances due to varying heights of firebed, the agitator will at all times maintain its position in or near the top of the lirebed.

The agitators being driven from beneath leaves the space abovethe firebed entirely unobstructed, which'is particularly desirable w'here the frebed is located under a boiler,

vfor example, or in other installations where the space above the trebed is otherwise preem ted.

prefer also to agitate the firebed from underneath through the medium of the ash. As shown in Fig. 1 a rotary pan 18 is located just beneath the irebed supporting member 3 and in conjunction with an annular skirt 19 depending from the sidewall 2, forms a water seal for the bottom of the irebed. The bottom agitation is obtained by one or more arms 20 and 21 extending up from the pan 18 into the ash bed, these arms serving to break up clinkers, stroke the ash downwardly and outwardly into the outer part of pan 18, and also to undulate the bottom part of the firebed, through the medium of the ash, and maintain 1the lower part of the firebed in uniform condition.

The above combination of parts provides a irebed which is held stationary by the sidewall and supporting member 3 and is nevertheless agitated at the top and bottom by the rotating mechanism operating at markedly different speeds. A rotary ash containing pan is also provided beneath the irebed which is very desirable for convenient ash disposal. Heretofore the above results have not been obtained due to the fact that the rotation of a pan at the bottom of the lirebed has caused a large part of the rebed to turn with it and has interfered with the proper relative motion between the agitating members and the irebed.

l,In the broader aspect of the invention it will be understood that similar general results may be obtained by rotating the rebed as a whole while holding the top and bottom agitating members against rotation, since the. same relative movements between the agitators and the parts of the firebed upon which they act, may be thus obtained. I consider l tirebed will be employed, the agitator 12 being rotated at a fairly rapid rate for example, one revolution in ten minutes, to fill up blow holes and keep the top of the firebed in a uniform condition. The bottom agitation, on the other hand, will usually be carried on at a much slower rate, just enough to produce a slow wave motion which extends progressively around the irebed as the arms 20 and 21 rotate, raising the irebed Vjust ahead of the arms and permit-ting it to drop back after the arms pass. The fuel feed screw 6 will usually rotate at a much more rapid rate than either the top or bottom agitator, for example, about ten revolutions per minute, while the bottom agitator rotates only about once or twice per hour. If complete combustion of the fuel is desired, the firebed will be thin! ner, and it is found that agitation of the nature above described, will maintain a condition so uniform in the firebed as to make it feasible to feed in substantially only that amount of air which is necessary to complete combustion, without requiring the large excess of air required in furnaces of present day type and which renders them very inefficient.

As another feature of the invention, the sidewall 2 may be provided with a metallic ring 22 at-its bottom which is in direct con- When an agitator is employed in connection with a fuel underfeed as above described, the central upwardly traveling column of fresh fuel eliminates the dead spots of ash which otherwise would tend to form directly above the tuyre hood, and the agitator levels off the top of the irebed and sweeps the fresh fuel out evenly over the same.

The symmetrical arrangement of the fuel feed, too and bottom agitating members, all operating concentrically about the central axis of the lrebed, also promotes uniformity of combustion throughout the firebed, the agitation serving to ll up any blowholes which may tend to form at the top, remove the ash uniformly around the irebed at the bottom, the bottom agitator breaking up any large clinkers which may tend to form, into sizes suliciently small to pass through the annular ash opening 26 between the pan 18 and skirt plied to a frebed which may be fed from the top in any suitable manner and provided with a sidewall 2, rebed supporting members 3, rotary pan 18 and surface agtitating member 12'* having a central stem 14, with driving mechanism adapted to keep the agitating .In Fig. 2 the invention is disclosed as api-- member 12 operating in the surface of the irebed, all as described above in connection with Fig. 1. i

In the form of the invention illustrated in Fig. 2, the air for combustion is supplied through a central tuyre hood 4a, through which the stern 14 of the top agitator extends, and bottom agitation is obtained by Water cooled arms 20n and 21a which are supported upon the rotary pan 18.

I also prefer to provide above the tuyrc hood 4a a rotary cap 27 having outstroking ribs 28 upon its upper surface and connected to the arms 21a by means of the pivoted links 29 which cause the cap to turn around with the bottom agitator to stroke outwardly the ash Which tends to build up over the tuyre hood, into the range of action of the agitator arms 21u which move the ash gradually out to the outer part of the rotary pan 18a. The links 29 also permit cap 28 to shift to some extent during its rotation, thereby permitting enough play to take up any cccentricitics in its circular motion.

In the form of the invention shown in Fig. 2 the sidewall 2 is provided with a Water cooled ring 22a to the bottom of which an annular skirt 19a is attached to provide a Water seal for the firebed. The agitator members 20, 21@l may be provided with interior vent pipes 30 to relieve the air pressure at the top and thereby permit the Water to rise to its full outside level.

While certain specific embodiments ofthe invention have been described, it will be obvious that many changes may be made there-l in Without departing from its principles as set forth in the appended claims.

I claim:

1. A rebed agitating mechanism, comprising a rotary agitating member adapted to work in the top portion of the firebed, means extending up from beneath the firebed for rotating said agitating member, means whereby the height of the agitating member is automatically regulated according to the resistance to turning which is exerted by the irebed, and a central fuel underfeed device adapted to feed in fuel to the central portion of the irebed beneath said agitating member. s

,2. A rebed agitating mechanism comprising an agitating member adapted to work in the top of the firebed, a second agitating member adapted to work in the ash bed, said agitating members being positioned to operate substantially coaxially, devices beneath the firebed for driving said top agitating member, and a separate device also located beneath the rebed for driving said second mentioned agitating member.

.3. In combination, an agitating member positioned to work in the top portion of the rebed, a hollow` column extending up into the frebed from beneath, a fuelfeed screw enclosed by said column, and a stem passing through the axis of said feed screw for driv ing said agitating member, said stem being rotatable with respect to the feed screw.

4. In combination, a irebed enclosing wall, means for feeding fuel up from underneath to the central portion of the firebed, means positioned to act in the surface of the irebed for spreading the fuel out from the central portion of the firebed toward the wall, and means positioned to operate in the bottom of the firebed also acting to spread the fuel out from the central portion of the firebed toward the wall, said fuel feeding means acting to deliver the fuel to the firebed at a level above the level of the innermost parts of the last mentioned spreading means.

5. In combination, a firebed enclosing Wall,

`means for feeding fuel up from underneath to the central portion of the lirebed, means acting in the top part of the rebed for directing fuel out from the central top portion of the irebed to maintain the peripheral portions of the top of the firebed at a level at least as high as the central top portion of the rebed, a firebed support, and a firebed agitating member located at the bottom of the iirebed and positioned to operate in an annular path surrounding the above mentioned central upward path of fuel feed and above said support.

6. In combination, a firebed enclosing wall, means for feeding fuel up from underneath to the central portion of the irebed, means automatically adjustable in accordance with the height of the firebed and acting in the top surface thereof for maintaining the peripheral top portions of the firebed at a level at least as high as the central top portion of the iirebed, a stem connected to said last mentioned means and extending down centrally 'through said fuel feeding means, a rebed agitating member acting in the bottom of the firebed and means for rotating said agitating member to sweep the same through the firebed in an annular pathi substantially concentric with said stern.

In testimony that I claim the foregoing, I have hereunto set my hand this 24th day of April, 1928.

WILLIAM B. CHAPMAN.

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